A component mounter performs work of using a component mounting head to pick up components supplied from a component supply device and mount the components on a circuit board. For example, as disclosed in the patent literature below, there are component mounting devices configured including multiple tape feeders that position a component at a supply position for the component mounting head, and multiple tape reels wound on which is component holding tape that holds multiple components. In recent years, because the types of boards and components is increasing, and component mounting work is becoming faster, it is desirable for many tape reels to be able to be set on a holding device for tools required for component supply such as the above tape feeders and tape reels. The cart used as a holding device for tools required for component supply disclosed in patent literature 1 below is provided with a reel holding section equipped on the rear side of a tape feeder that holds a component holding tape in a manner where supply to the tape feeder is possible, a reel stock section provided below the reel holding section for stocking spare tape reels, and a large reel holding section provided below the reel stock section for holding large reels on which is wound large component holding tape larger than component holding tape that can be held by the reel holding section and the reel stock section. Also, the component supply device disclosed in patent literature 2 below is able to increase the quantity of tape reels that can be set in a given width by positioning multiple of the tape reels at alternating positions in a vertical direction.